Receive the latest investigations updates in your inbox

Moffet Field Toxic Plume Concerns

The Environmental Protection Agency (EPA) now says the area affected by toxic TCE is larger than initially thought and that the Agency may have missed higher than acceptable levels of TCE in some homes outside the original plume area. (Published Friday, Feb. 22, 2013)

There are new concerns about a toxic plume of chemicals lurking underground in and around Moffett Field and Mountain View.

The Environmental Protection Agency (EPA) now says the area affected by toxic TCE is larger than initially thought and that the Agency may have missed higher than acceptable levels of TCE in some homes outside the original plume area.

The plume is about a mile and a half long by a half mile wide and is registered by the Environmental Protection Agency (EPA) as the as “Middlefield-Ellis-Whisman (MEW) Study Area” Superfund site.

NBC Bay Area’s Investigative Unit first dug into this toxic plume and its implications for residents’ health a year ago. The Investigative Unit’s initial probe then prompted California’s cancer registry to open its own investigation. After several months the cancer registry found a higher than expected incidence of certain cancers among residents living during certain time periods in the area..

What experts find most troubling about this news is that EPA officials admit they don’t know how long this underground chemical plume has been leeching into the air in two different “hot spots.”

The chemical has been found by the EPA in the air in higher than acceptable concentrations in two homes where residents could have been breathing it for years.

The EPA has been monitoring and extracting toxic Trichloroethyle or T-C-E from groundwater and soil in and around Moffett Field and in Mountain View along Whisman Road, South to Middlefield Road and east to Ellis Street.

TCE was used a cleaning solvent once commonly used by the military and the budding semi-conductor industry 30 years ago.

Several years after its common use experts discovered TCE was, in fact, a toxic solvent that causes cancer in people and heart deformities in unborn babies.

The toxic solvent leaked from underground tanks and spilled all over the area which is why the neighborhood around Moffett Field is an official EPA Superfund site.

“We cleaned up over 5 ¼ billion gallons of contaminated ground water and treated over 100,000 pounds of toxic contaminant,” said Alana Lee the EPA Superfund Site Project Manager for this site.

But EPA officials now admit they missed what they’re now calling “hotspots” located along Evandale Avenue, including high levels of T-C-E contamination in two residents along Evandale. Those homes are located outside of the original area that EPA officials thought was the boundary of the M-E-W plume.

“The concentration is very a very high concentration,” said the EPA’s Lee.

The highest T-C-E levels that the EPA measured in ground water in the area reached 130,000 parts per billion. The EPA considers anything over 5 parts per billion unsafe.

“Once we found these concentrations, which were a surprise, we took immediate action,” said Superfund Site Manager Lee.

The EPA also found TCE in more than 20 different commercial buildings in the area located above.

EPA officials say this plume will likely take decades to clean up.

Included among them are two new Google office buildings where apparently renovations to the concrete slabs allowed higher expected than levels of TCE to leech into the air inside the buildings where Google employees work.

I asked the EPA if they knew exactly how long have these hot spots had been there? “We don’t know,” said the EPA’s Lee.

EPA officials were so concerned about the levels of TCE in the homes along Evandale that they immediately began putting ventilation systems in them. One is complete. The other is expected to be finished in the coming weeks.

As for the office buildings, including Google’s, the EPA says they have systems to keep vapors outside the buildings.

Google representatives said they take this matter seriously and they’ve taken measures to ensure that the area is safe.

After NBC Bay Area inquired about cancer rates among residents living in and around the Moffett Field or MEW Superfund site, the state cancer registry began its own scientific investigation.

California’s state cancer registry announced that after exhaustive research and analysis of three decades worth of health data it found a higher than expected number of people living in Horton’s neighborhood who contracted a group of cancers the registry’s scientists call non-Hodgkin lymphoma.

The higher than expected incidence of these cancers occurred during the years 1996 to 2005.